A curable fluorocarbon elastomer is dynamically cured in the presence of a major amount of a non-curing thermoplastic material and a minor amount of a second fluorocarbon elastomer that does not cure under the dynamic vulcanization conditions. The non-curing elastomer is preferably present at from 1 to 20 parts based on 100 parts of the curing fluorocarbon elastomer. Processable rubber compositions comprise a continuous phase of a thermoplastic material, particles of a cured fluorocarbon elastomer dispersed in the continuous phase, and an uncured fluorocarbon elastomer at a level of 10 parts or less per 100 parts of the cured fluorocarbon elastomer. Shaped articles such as gaskets and seals are produced by thermoplastic processing of the processable rubber compositions.